This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth,” said lead researcher Nikku Madhusudhan, a Yale postdoctoral researcher in physics and astronomy. “The surface of this planet is likely covered in graphite and diamond rather than water and granite.”

The paper reporting the findings has been accepted for publication in the journal Astrophysical Journal Letters.

Illustration of the interior of 55 Cancri e — an extremely hot planet with a surface of mostly graphite surrounding a thick layer of diamond, below which is a layer of silicon-based minerals and a molten iron core at the center. (Image by Haven Giguere)

The planet has been called a “super-Earth” and was discovered in 2004, according to NBCNEWS.com. Its mass is about 8 times greater than Earth’s and is in the Milky Way Galaxy.

Yale says it is visible to the naked eye in the constellation of Cancer.

Scientists thought the planet’s chemical makeup is similar to Earth and that it was covered with superheated water.

But no, Yale says:

..the new research suggests the planet has no water at all, and appears to be composed primarily of carbon (as graphite and diamond), iron, silicon carbide, and, possibly, some silicates. The study estimates that at least a third of the planet’s mass — the equivalent of about three Earth masses — could be diamond.